Field of the Invention
The present invention relates to a display control apparatus.
Description of the Related Art
An image display apparatus is available that can display an image having high resolution, such as with a number of horizontal effective pixels [3840]×a number of vertical effective lines [2160]. Hereafter “a number of horizontal effective pixels X×a number of vertical effective lines Y” is expressed as “X×Y”. In image production fields that produce images for broadcasting, movies and the like, an image output apparatus may send a plurality of partial image data, which represent a plurality of partial images constituting a high resolution image, to an image display apparatus via a plurality of cables. Then the image display apparatus may simultaneously display the plurality of partial images represented by the plurality of partial image data. The image display apparatus displays the high resolution image by simultaneously displaying the plurality of partial images. For the cable, a serial digital interface (SDI) cable, for example, is used.
For example, an image display apparatus supporting a 3840×2160 resolution acquires four partial image data, each of which represents a partial image having a 1920×1080 resolution, from the image output apparatus via four cables. Then the image display apparatus simultaneously displays the four partial images, represented by the four partial image data, on four different screen regions. Thereby the image display apparatus displays an image having a 3840×2160 resolution.
There is another image display apparatus that has a display mode in which a plurality of partial images are simultaneously displayed on a plurality of screen regions (multi-display mode), and a display mode in which one selected partial image is displayed on the entire screen (single-display mode). In the above mentioned image production fields, images having various resolutions are produced. For example, in the above mentioned image production fields, an image having a 3840×2160 resolution (first production image) is produced, or an image having a 1920×1080 resolution (second production image) is produced. To display the first production image, the image output apparatus generates a plurality of partial image data from first production image data (image data representing the first production image), and sends the plurality of partial image data to the image display apparatus via a plurality of cables. To display the second production image, the image output apparatus sends second production image data (image data representing the second production image) to the image display apparatus via one cable. Therefore it is preferable to set the multi-display mode to display the first production image, and to set the single-display mode to display the second production image.
Japanese Patent Application Laid-open No. 2006-086866 discloses a technique to select the single-display mode in a case where image data is acquired by only one of a plurality of input terminals, and to select a multi-display mode in a case where image data is acquired by all of the plurality of input terminals.
In some cases, however, all the cables may be constantly used to transmit image data from the image output apparatus to the image display apparatus. For example, to display the second production image, the image output apparatus may send second production image data to the image display apparatus via one cable, and send dummy image data to the image display apparatus via the rest of the cables. At least one of: color, brightness, frame rate, transmission format (e.g. interface format, progressive format), resolution and the like of the dummy image data is different from that of the second production image data. For example, the dummy image data represents an image with a single color (single color green).
According to the technique disclosed in Japanese Patent Application Laid-open No. 2006-086866, the multi-display mode is selected in a case where the second production image data is acquired by one input terminal, and dummy image data is acquired by the rest of the input terminals. As a result, the second production image is displayed in one of the plurality of screen regions, and a dummy image (image expressed by the dummy image data) is displayed in the rest of the screen regions. This type of image display is quite unsightly. In this way, with the technique disclosed in Japanese Patent Application Laid-Open No. 2006-086866, an inappropriate image (unsightly image) may be displayed.
Japanese Patent Application Laid-open No. 2015-060021 discloses a technique to select the multi-display mode or the single-display mode based on the resolution of the acquired image data. In concrete terms, the single-display mode is selected if two or more low resolution image data are acquired. However, according to the technique disclosed in Japanese Patent Application Laid-open No. 2015-060021, the multi-display mode is selected if the second production image data is acquired by one input terminal, and dummy image data having high resolution is acquired by the rest of the input terminals. Therefore, even with the technique disclosed in Japanese Patent Application Laid-open No. 2015-060021, an inappropriate image (unsightly image) may be displayed.